Receiving a Director Penalty Notice starts a 21-day clock from the issue date....

https://dlf-ne.org/how-do-i-spot-a-lockdown-dpn-before-the-client-wastes-money-on-the-wrong-step/

Receiving a Director Penalty Notice starts a 21-day clock from the issue date. You need to distinguish between lockdown and non-lockdown notices to protect your client effectively